Abstract
Predator-prey interactions are quite common in many natural ecosystems
as well as in waste treatment bioreactors. The study of predation is therefore
important for understanding the dynamics of ecosystems and is also important
for the optimization of the biological treatment of wastes. In activated sludge
reactors, for instance, protozoa is known to play a valuable role by preying on
unflocculated bacteria and thereby clarifying the reactor effluent [41].